In one of the most comprehensive oil field carbon intensity (CI) studies ever published, a global team led by Stanford University has calculated the CI of the world’s active oil fields — with significant results for Saudi Arabia.

CI is a measure of the greenhouse gas emissions associated with producing crude oil, from the well to the refinery gate.

Low marks, good marks

The scientists discovered that among the countries producing more than 0.1% of global oil production, Saudi Arabia ranks the lowest in CI of any major producer to extract, process, and transport its crude oil to the refinery gate.

With a CI measurement of 4.6 grams of carbon dioxide (CO2) equivalent per each megajoule, which is approximately 27 kg of CO2 equivalent per barrel of crude oil, Saudi Arabian oil is second only to the lowest in the world, Denmark, which produces almost 150,000 barrels of oil per day.

“Saudi Arabia is the largest global oil producer, but has a small number of extremely large and productive reservoirs,” the report states. “The country has low per-barrel gas flaring rates and low water production — resulting in less mass lifted per unit of oil produced and less energy used for fluid separation, handling, treatment, and reinjection — thereby contributing to low CI.

Collective industry effort

Speaking before the Oil and Gas Climate Initiative (OGCI) annual stakeholder meeting in New York last week, Saudi Aramco president and CEO Amin Nasser said the study confirmed the significant greenhouse gas mitigation potential of Saudi crude oil.

At the New York meeting, the CEOs of the OGCI’s 10 existing member companies and three new members — ExxonMobil, Chevron, and Occidental — discussed the industry’s approaches to decrease greenhouse gas emissions with key stakeholders. The OGCI also unveiled plans to reduce its collective, average methane intensity of core upstream oil and gas operations to below 0.25% by 2025, with a goal of reaching 0.2% corresponding to a reduction by one-third.

Crucial global consideration

With oil demand remaining significant for the coming decades, prioritizing the use of low CI oils is a crucial global consideration for climate change.

Oil demand will also be driven by increased demand for chemicals, which is expected to double over the next 25 years. In the meantime, oil needs to be sourced in the most carbon-responsible manner, and the paper recommends investing in technology as one way to reduce CI.

The LDAR program has been implemented Kingdomwide across all company operations and is now being optimized by assessing and introducing new cost-effective methane monitoring technologies such as thermal cameras, laser detection, and quantification sensors.

A world leader in minimizing routine flaring — with a flaring intensity level of less than 1% — Saudi Aramco is also using technologies such as mobility geosteering, multilateral wells with smart completions, and peripheral water flooding, which have led to low water production per barrel and less energy consumption, resulting in lower carbon emissions.

Vast amounts of data

The Science journal study analyzed vast amounts of publicly available data for both onshore and offshore wells, as well as conventional and unconventional resources.

The team calculated the CI of crude oil well-to-refinery gate across exploration, drilling, development, production, extraction, surface processing, and transport to the refinery inlet.

With data from more than 800 references, the study covers 98% of global oil and condensate production in 2015. It is the first time such an analysis was done at this very resolved oil field-by-field level.

Scientists from the Aramco Research Center in Detroit coauthored the paper, along with scientists from 14 global academic and policy institutions. The Aramco team included Hassan El-Houjeiri, Alhassan Badahdah, Jean-Christophe Monfort, and Steve Przesmitzki.

Previously, a better understanding of crude oil greenhouse gas emissions was generally hindered by a lack of a single method for measuring the CI of oils.

The team used the Oil Production Greenhouse Gas Emissions Estimator (OPGEE) which was originally developed by Stanford University. The OPGEE development was instrumental for the ever-increasing use of data-driven CI analysis by regulators and private investors.

“The development of the OPGEE model solved a big part of the puzzle by providing a peer-reviewed, open source tool for measuring the carbon intensity of oils,” said El-Houjeiri.

Significant potential

Selectively and innovatively managing the different properties of the world’s crude oils has significant potential to mitigate greenhouse gas emissions.

Producing, transporting, and refining crude oil into fuels such as gasoline and diesel account for up to 40% of transport fuels emissions, depending on the field. The study identified two strong factors influencing CI: flaring, and water cut.

The paper recommends that new and existing oil fields could lower CI by a number of means, including incorporating CO2 capture, eliminating routine flaring and capturing fugitive methane emissions.

‘Leading position in the industry’

Giving a quantitative value to the advantage Saudi Arabia has in a carbon constrained world, the paper shows how much carbon could be saved by simply switching crude supplies. It shows that at least 18 metric gigatons of CO2 equivalent could be saved over the century by reducing oil sector emissions through selection of low CI crude resources, as well as improved gas management practices.

“The findings presented in the paper unequivocally confirm Saudi Aramco’s leading position in the oil industry in terms of carbon intensity,” commented Ahmad O. Al-Khowaiter, chief technology officer of Saudi Aramco. “We are committed to continuing our efforts to maintain this leadership.”